By social mobility is understood any transition of an individualor social object or value–anything that has been created or modifiedby human activity–from one social position to another. There are twoprincipal types of social mobility, horizontal andvertical.. By horizontal social mobility or shifting, is meantthe transition of an individual or social object from one socialgroup to another situated on the same level. Transitions ofindividuals, as from the Baptist to the Methodist religious group,from one citizenship to another, from one family (as a husband orwife) to another by divorce and remarriage, from one factory toanother in the same occupational status, are all instances of socialmobility. So too are transitions of social objects, the radio,automobile, fashion, Communism, Darwin’s theory, within the samesocial stratum, as from lowa to California, or from any one place toanother. In all these cases, “shifting” may take place without anynoticeable change of the social position of an individual or socialobject in the vertical direction. By vertical social mobilityis meant the relations involved in a transition of an individual (ora social object) from one social stratum to another. According to thedirection of the transition there are two types of vertical socialmobility: ascending and descending, or socialclimbing and social sinking. According to the nature ofthe stratification, there are ascending and descending currents ofeconomic, political, and occupational mobility, not to mention otherless important types. The ascending currents exist in two principalforms: as an infiltration of the individuals of a lowerstratum into an existing higher one; and as a creation of a newgroup by such individuals, and the insertion of such a group into ahigher stratum instead of, or side by side with, the existing groupsof this stratum.. Correspondingly, the descending current hasalso two principal forms: the first consists in a dropping ofindividuals from a higher social position into an existing lower one,without a degradation or disintegration of the higher group to whichthey belonged; the second is manifested in a degradation of asocial group as a whole, in an abasement of its rank among othergroups, or in its disintegration as a social unit.. The firstcase of “sinking” reminds one of an individual falling from a ship;the second of the sinking of the ship itself with all on board, or ofthe ship as a wreck breaking itself to pieces.
The cases of individual infiltration into an existing higherstratum or of individuals dropping from a higher social layer into alower one are relatively common and comprehensible. They need noexplanation. The second form of social ascending and descending, therise and fall of groups, must be considered more carefully.
The following historical examples may serve to illustrate. Thehistorians of India’s caste-society tell us that the caste of theBrahmins did not always hold the position of indisputable superioritywhich it has held during the last two thousand years. In tlle remotepast, the caste of the warriors and rulers, or the caste of theKshatriyas, seems to have been not inferior to the caste of theBrahmins; and it appears that only after a long struggle did thelatter become the highest caste.  If this hypothesis be true, thenthis elevation of the rank of the Brahmin caste as a whole throughthe ranks of other castes is an example of the second type of socialascent. The group as a whole being elevated, all its members, incorpore, through this very fact, are elevated also. Before therecognition of the Christian religion by Constantine the Great, theposition of a Christian Bishop, or the Christian clergy, was not ahigh one among other social ranks of Roman society. In the next fewcenturies the Christian Church, as a whole, experienced an enormouselevation of social position and rank. Through this wholesaleelevationl of the Christian Church, the members of the clergy, andespecially the high Church dignitaries, were elevated to the highestranks of medieval society. And, contrariwise, a decrease in theauthority of the Christian Church during the last two centuries hasled to a relative abasement of the social ranks of the high Churchdignitaries within the ranks of the present society. The position ofthe Pope or a cardinal is still high, but undoubtedly it is lowerthan it was in the Middle Ages.  The group of the legists inFrance is another example. In the twelfth century, this groupappeared in France, as a group, and began to grow rapidly insignificance and rank. Very soon, in the form of the judicialaristocracy, it inserted itself into the place of the previouslyexistiug nobility. In this way, its members were raised to a muchhigher social position. During the seventeenth, and especially theeighteenth centuries, the group, as a whole, began to “sink,” andfinally disappeared in the conflagration of the Revolution. A similarprocess took place in the elevation of the CommunalBourgeoisie in the Middle Ages, in the privileged Six Corps orthe Guilda Mercatoria, and in the aristocracy of manyroyal courts. To have a high position at the court of the Romanoffs,Hapsburgs, or Hohenzollerns before the revolutions meant to have oneof the highest social ranks in the corresponding countries. The”sinking” of the dynasties led to a “social sinking” of all ranksconnected with them. The group of the Communists in Russia, beforethe Revolution, did not have any high rank socially recognized.During the Rwolution the group climbed an enormous social distanceand occupied the highest strata in Russian society. As a result, allits members have been elevated en masse to the place occupiedby the Czarist aristocracy. Similar cases are given in a purelyeconomic stratification. Before the “oil” and “automobile” era, to bea prominent manufacturer in this field did not mean to be a captainof industry and finance. A great expansion of these industries hastransformed them into some of the most important kinds of industry.Correspondingly, to be a leading manufacturer in these fields nowmeans to be one of the most important leaders of industry andfinance. These examples illustrate the second collective form ofascending and descending currents of social mobility.
From Pitirim Sorokin, Social and Cultural Mobility. NewYork: The Free Press, 1959.